Safety drill pipe float valve with heat responsive shut off sleeve



I United States- Patent 111] 3,537,518

[72] Inventors Wayne M. Sullivan and [56] References Cited v John W. Turner, J12, Houston, Texas UNITED STATES PATENTS l P 2 2.858.838 11/1958 Scaramucci 166/225X [221 Flled 3 151 688 10/1964 YOun 17s/71x 14s Patented Nov.3, 1970 g i [73] Assignee Byron Jackson, Inc. 3,245,423 4/1966 Hansen etal. 137/75X g Beach California 3,332.49? 7/1967 Hams et al. 166/225X a corporation of Delaware Primary ExaminerMarvin A. Champion Assistant Examiner-Ian A. Calvert Attorneys- Donald W. Banner, Lyle S. Motley, C. G. Stallings and William S. McCurry 1 SAFETY DRILL PIPE FLOAT VALVE ABSTRACT: A safety drill pi e float for use when air is RESPONSWE H P SLEEVE employed as the drilling fluid and in which the valve seat is 7claimss Drawmg formed as part of a sleeve fixed in an upper position for [52] [1.8. CI. 166/64, engagement by the valve head by a bonding agent, such as 166/225; 137/75, 137/515.7: 175/71, 175/232 solder or babbitt which is heat sensitive so as to be liquefied [51 Int. Cl E2lb 35/00; in the event of a bore hole fire. the sleeve moving to a lower Fl6k l7/40 position when the bonding agent is liquefied to engage the [50] Field of Search 166/64, valve head and shut off the flow of air through the drill 224. 225; l75/7l,232, 318: 137/75, 5 l5-5l5.7/(lnquired) string to prevent further combustion.

Patented Nov. 3, 1970 3,537,518

Sheet 1 of 2 \muwm mmw\% \Nik\\\\ INVFNTORS. W/W/V M swam/v WZK (9. ATTOEA/G SAFETY DRILL IIPE FLOAT VALVE WITH HEAT RESPONSIVE SHUT OFF SLEEVE BACKGROUND OF THE INVENTION In the drilling of some oil and/or gas wells it is the practice to employ air as a drilling fluid which is pumped downwardly through the string of drill pipe, through the bit, and into the annular space outside the drill string to carry cuttings to the surface. In such well a fire may be caused when combustible gas or oil is encountered. If the fire is undetected it is enhanced by the continued pumping of air to support the combustion, and serious consequences may result.

In the drill string there is ordinarily employed a so-callcd drill pipe float which comprises a valve adapted to be normally closed during running of the drill string into the well bore to prevent the upward passage of air and cuttings into the drill string but the valve being held open by the downward flow of drilling fluid during drilling. However, when drilling fluid circulation is interrupted, the valve automatically closes to prevent back flow ofdrilling fluid through the bit into the drill string. If a fire in the bore hole is detected the circulationof drilling air can be stopped so as to not feed air to the fire. and at the same time the valve will automatically close.

To date, however, there has been no satisfactory mode of automatically shutting off the flow ofair to the bore hole when the fire commences.

SUMMARY OF THE INVENTION The present invention provides a drill pipe float valve which is adapted to automatically close in the presence of a down hole fire.

More particularly, the invention employs a drill pipe float so modified that a valve sleeve will shift from a normal position to a second position in engagement with the float valve head.

In accomplishing the foregoing, a sleeve having the usual float valve seat thereon is fixed in an initial position by a medium responsive to heat for releasing the sleeve, so that the sleeve is moved by fluid pressure to a second position of engagement with the valve head while the latter is in its open position, thereby shutting off the flow of air into the well bore through the drill string and causing an increase in air pumping pressure at the surface to indicate to the driller that a tire exists in the well bore.

Other objects and advantages of the invention will be hereinafter described or will become apparent to those skilled in the art, and the. novelfeatures of the invention will be defined in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view in longitudinal section showing the drill pipe float in a normal closed position;

FIG. 2 is a view corresponding to FIG. 1, butshowing the valve open;

FIG. 3 is a transverse section, as taken on the line 3-3 of FIG. 1',

FIG. 4 is a transverse section, as taken on the line 4-4 of FIG. I; and

FIG. 5 is a view in longitudinal section showing the valve in emergency closed condition.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, 'a valve mechanism V is incorporated in a string of drill pipe or drill collar D which is adapted to extend to the top of the well bore, and through which drilling fluid is pumped in a downward direction as the drill string is rotated to rotate a drill bit on its lower end, the drill bit sub being designated B. The valve V may be incorporated at any convenient location along the drill string D, but, as here shown, it is mounted in a short drill collar sub ordinarily placed just above the bit sub B. The drillcollar sub 10 has an enlarged bore 11 providing a cylindrical wall and a lower radial shoulder 12. Illustratively, the sub 10 has a lower threaded pin 13 engaged in the upper threaded box 14 of the bit sub B. The upper end of the sub 10 is constituted as a threaded box 15 secured to the lower pin end I6 of the adjoining drill collar or pipe section 17. The lower shoulder 12 and the lower end 18 of the collar or pipe section l7 provide axially spaced abutments between which the valve assembly V now to be described is disposed.

The valve assembly V includes a body 20 adapted to fit in the bore ll of collar 10, and the length ofthe body 20 may be slightly less than the distance between the shoulders 12 and I8. Illustratively, the body 20 includes an upper cylindrical portion 2| provided with sealing ring means, such as an O-ring 22 for sealing engagement within the bore II to prevent bypass of fluid about the outside of the body 20 and resultant erosive wear.

At its lower end, the body 20 has a lower cylindrical portion 23 adapted to flt within the bore 11. Otherwise, the body 20 may be oflesser diameter than the bore 11.

Internally, the body is provided with a valve chamber 24 having an upwardly tapered conical surface 25 constituting a valve seat which circumscribes a flow passage 26 which extends between the upper end of the body 20 and the valve chamber 24. Reciprocable in the valve chamber 24 is a valve head 27, this head being supported and centered on a valve stem 28 and spring biased to a seated position (FIG. 1) by a coiled compression spring 29 which abuts at its upper end on an internal shoulder 30 in the head 27 and which seats at its lower end on a spider-like supporting disc 31.

This disc 31 seats in a bore 32 at the lower end of the valve body 20, there being a downwardly facing shoulder 33 engaged by the disc 31, and a snap ring 34 or other retainer means being employed to retain the disc 31 in place. The valve stem 28 is formed integral with the disc 31 and projects upwardly therefrom into a reduced cavity 35 formed in the underside of the valve head 27. Depending, in encircling relation to the spring 29, from the shoulder 30 is a skirt 36 which, when the valve is open (FIG. 2) shields the spring 29 and the stem 28 from the erosive action of drilling lluid flowing downwardly past the valve head and through a number of ports 37 formed in the disc 31. The upper end of the valve head 27 is formed as a conical frustum 38 corresponding to a conical seat 25 for effectively sealing the valve assembly against the upward flow offluid when the valve is closed.

The construction described above is a durable one, in that the head 27 is separate from the stem 28 and is a one piece construction. The stem 28 is durable in that it is an integrated unit with the disc 31 and is shielded by the skirt 36 during exposure to maximum wear.

Reference to FIG. 3 shows to best advantage that the cavity 35 in the valve head 27 is non-circular or square in cross section, and likewise, the upper end portion 280 of the stem 28 is correspondingly nomcircular or square in cross section, whereby the valve head is incapable of spinning on the stem 28 as would be the case were the pin circular. Thus, the connection between the valve head 27 and the stem is not subject to rapid wear due to relative movement in an abrasive environment during drilling operations.

In use, the valve V will be normally closed during running of the pipe string into the well bore, so that the entry of fluid into the drill string with cuttingsentrained in the fluid is prevented. the tendency of the bit orifices to be plugged thereby being substantially reduced. However, when drilling fluid circulation resumes, the valve will be opened but held against spinning of the head by the non-circular engagement between the stem and head, the stem and the valve spring being protected from the erosive action ofthe drilling fluid.

The valve is a combined poppet and sleeve valve in the illustrative embodiment, in that above the conical portion 38 of the valve head 27 there is formed an upwardly extended sleeve 40. This sleeve section 40 extends into the flow passage 26 a.

in order to permit the downward flow of drilling fluid or air through the valve assembly when the valve is open (FIG. 2). the sleeve 40 has a central bore 41 therein and a plurality of radially opening and circumferentially spaced and extended ports 42. Preferably, the ports have a combined flow area equal to or greater than the flow area through the valve in the absence of the sleeve 40 and ports 42 so that no restriction to flow is caused thereby.

As previously indicated, the subject valve is adapted to automatically close in the event that a down hole fire creates heat. Thus, the valve body is a composite structure, including the internal sleeve 43 which is disposed within an upper bore 44, the sleeve 43 providing the above-mentioned flow passage 26 and having the conical valve seat at its lower end. The sleeve 43 has a bottom flange 45 which projects radially outward to form an upwardly facing shoulder 46 which is adapted to engage a downwardly facing body shoulder 47 to prevent upward movement of the sleeve 43 within the body 20. Thus, the sleeve 43 can withstand substantial upward force when the valve is closed.

The sleeve 43 is held in the upper position, with shoulders 46 and 47 engaged, by means which releases the sleeve 43 for downward movement responsive to excessive heat. Such means is here shown as a layer of bonding material 48 interposed between or at the interface of the sleeve 43 and the wall of the body bore 44. This bonding material may be lead solder, babbitt or other thermoplastic material having a suitable melting point, whereby when fire in the well causes the bonding agent to liquefy, the sleeve 43 will be released for downward movement to the emergency closed position of FIG. 5, at which the sleeve 43 has moved downwardly to contact the valve head 27, shutting off ports 42 and engaging seat 25 on the valve head surface 38.

Under these circumstances, further downward flow of drilling fluid or air will be prevented, causing an increase in pressure in the air pumping system to indicate to the driller that the valve is closed. Since the flow of air is shut off, the

further combustion in the hole will not be supported by the continued pumping ofair to the fire.

Variation in the details of construction may be resorted to without departing from the spirit of the invention.

lclaim:

1. In a drill pipe float having a valve body provided with portions adapted to be engaged in the bore of a drill collar sub, a downwardly tapered valve seat in said body, a flow passage circumscribed by said seat, a valve head reciprocable in said body between a position engaged with said seat and an open position displaced downwardly from said seat, a valve stem supporting said head, and spring means acting on 'said head to bias the same into engagement with said seat, the improvement wherein said body includes a sleeve having said flow passage and said seat, said sleeve being movable between an upper position engageable by said head and a lower position in engagement with said head. and means responsive to excessive heat for releasably maintaining said sleeve in said upper position.

2. A drill pipe float as defined in claim 1, wherein said means responsive to excessive heat is a material which melts in the presence ofexcessive heat.

3. A drill pipe float as defined in claim material is a metal.

4. A drill pipe float as defined in claim material is a solder.

5. A drill pipe float as defined in claim material is babbitt.

6. A drill pipe float as defined in claim 1. wherein said sleeve has an upwardly facing shoulder and said body has a downwardly facing shoulder, said shoulders being coengaged when said sleeve is in said first position.

7. A drill pipe float as defined in claim 1, wherein said valve head has an upwardly extending cylindrical portion disposed in said sleeve, said portion having a central bore and a radially opening port for the flow offluid when said valve is open.

2, wherein said 2, wherein said 2, wherein said 

